CPU Bottleneck Exposed By GeForce GTX 1080 Ti?

Last week, NVIDIA released the GeForce GTX 1080 Ti Founders Edition graphics card. This is the fastest desktop consumer graphics card in the world and we were torn on how we wanted to test it. We are in the middle of updating out GPU test bench and are fighting a few hardware gremlins and we thought we'd try something new and a little different for a change. AMD just recently launched it's Ryzen processor series and that is a huge architectural change for AMD. It's been many years since we've run graphics cards benchmarks on an AMD platform since Intel has been the platform of choice for gaming performance. Has that changed?
So, rather than comparing the Intel GeForce GTX 1080 Ti Founders Edition graphics card to dozens of other video cards we are going to be comparing it to just the NVIDIA GeForce GTX 1080 Founders Edition, but on two different platforms. One will be powered by a stock Intel Core i7-7700K processor ($329.99) and the other will be powered by the AMD Ryzen 7 1700 ($329.99). Both systems have Corsair Hydro series CPU water coolers and are running the same exact Corsair Vengeance LPX 16GB of DDR4 memory kit at 2933 MHz with CL14 timings. We tried to make the platforms as identical as possible as we wanted to see how the GPU would scale at 1080P, 1440P and 4K resolutions when powered by latest Intel Core i7 Kaby Lake and AMD Ryzen 7 processors. We also gave the AMD Ryzen 7 1700 a head start by overclocking it from 3.0GHz (3.7GHz Turbo) stock clock speeds all the way up to 4GHz on all 8-cores. The Intel Core i7-7700K 'Kaby Lake' processor was left at stock settings, which are 4.2GHz base and 4.5GHz boost.
[caption id="attachment_192243" align="aligncenter" width="645"] AMD Ryzen 7 1700 With ATI Ruby[/caption]
We've all heard that AMD Ryzen 7 series processors don't perform that hot at 1080P resolutions, so we'll be paying close attention to how the GPU performance scales when you move from the GeForce GTX 1080 to the GeForce GTX 1080 Ti. We've been slowly coming to the point that the GPU is going to be bottle-necked a little by the processor on both platforms. This greatly depends on the game title you are looking at, so we wanted to take a quick look at a few game titles.
Depending on how much traffic this article gets we might expanding testing and look at more processors in the future as we do see CPU bottlenecks becoming an increasing concern for many. Keep in mind that CPU bottlenecks are more prevalent at lower resolutions and graphics settings. Once you increase the resolution or image quality settings you'll likely become more GPU bound and the CPU bottleneck will be lessened.
That said, let's look at the test systems and then jump into the benchmarks.

AMD & Intel Test Systems

The AMD AM4 platform that we used to test the Ryzen 7 1700 was running the MSI X370 Xpower Gaming Titanium motherboard with UEFI 1.22 that came out on 03/02/2017. The processor was overclocked to 4.00 GHz on all cores with 1.3875V set for the CPU Core voltage. The Corsair Vengeance 16GB 4000MHz DDR4 dual channel memory kit was manually set to 2933MHz with 14-14-14-28 1T memory timings as we wanted to test with one of the most popular clock frequencies sold today. We used an NVIDIA GeForce GTX 1080 8GB Founders Edition and GeForce GTX 1080 Ti 11GB Founders Edition video card with GeForce 378.78 WHQL drivers. We also used the Corsair AX860i digital power supply, Corsair Hydro Series H110i water cooler and Corsair Force MP500 480GB PCIe SSD on the system.

The Intel Z270 platform that we used to test the Intel 1151 processors was running the Gigabyte Aorus Z270X-Gaming 5 with UEFI F5e that came out on 12/28/2016. The Corsair Vengeance 16GB 4000MHz DDR4 dual channel memory kit was manually set to 3000MHz with 15-15-15-36 1T memory timings as we wanted to test with one of the most popular clock frequencies sold today. We used an NVIDIA GeForce GTX 1080 8GB Founders Edition and GeForce GTX 1080 Ti 11GB Founders Edition video card with GeForce 378.78 WHQL drivers. We also used the Corsair AX860i digital power supply, Corsair Hydro Series H105 water cooler and Crucial MX300 1050GB SSDs on the system.

Another thing to note is that we will be testing on 3DMark Fire Strike and five game titles. The games selected were done at random and from our own picking based on release dates.
Thief: February 25, 2014
Grand Theft Auto V: April 14, 2015
Fallout 4: November 10th, 2015
Deus Ex: Mankind Divided: August 23rd, 2016
Tom Clancy's Ghost Recon Wildlands: March 7, 2017
These five game titles span the past three years and use both DX11 and DX12 API's. We wanted to show CPU/GPU performance on new and old game titles, so we think these covers do that well.

3DMark Fire Strike and Deus Ex: Mankind Divided

Futuremark 3DMark Fire Strike

3DMark Fire Strike is the new showcase DirectX 11 benchmark for high-performance gaming PCs. Using a multi-threaded DirectX 11 engine, Fire Strike includes two graphics tests, a physics test and a combined test designed to stress the CPU and GPU at the same time. 3DMark Advanced and Professional Editions include an additional Extreme preset for highend systems with multiple GPUs. Fire Strike is only available in the Windows editions of 3DMark initially.
3DMark Fire Strike Physics test benchmarks the hardware’s ability to run gameplay physics simulations on the CPU. The GPU load is kept as low as possible to ensure that only the CPU is stressed. The Bullet Open Source Physics Library is used as the physics library for the test. The test has 32 simulated worlds. One thread per available CPU core is used to run simulations. All physics are computed on CPU with soft body vertex data updated to GPU each frame.

Results: The Intel Core i7-7700K 'Kaby Lake' processor running at stock speeds was able to score higher in the GPU benchmark, but gets crushed by the AMD Ryzen 7 1700 overclocked to 4 GHz on all cores in the Physics test. Due to how Futuremark weights the test the overall score between the two processors is pretty close to one another. Both processors scale nicely by moving from the NVIDIA GeForce GTX 1080 FE to the NVIDIA GeForce GTX 1080 Ti as we saw a 22.2% gain on the AMD Ryzen 7 1700 overclocked and a 22.4% gain on the Intel Core i7 7700K.

Deus Ex: Mankind Divided

Deus Ex: Mankind Divided is an action role-playing stealth video game developed by Eidos Montreal and published by Square Enix. Set in a cyberpunk-themed dystopian world in 2029, two years after the events of Human Revolution, Mankind Divided features the return of Adam Jensen from the previous game, Deus Ex: Human Revolution, with new technology and body augmentations. The game was released on August 23rd, 2016 for PC users.

Deus Ex: Mankind Divided uses a heavily modified version of the Glacier 2 engine that has been tweaked so much that they are now calling it the Dawn game engine.

We took a look at GPU performance using the DX12 API setting paired with the ‘Medium’ image quality preset with MSAA and VSync turned off. We picked to run just ‘Medium’ image quality settings due to how tough this game title is to render and we feel that most gamers will use this setting.
Benchmark Results:In Deus Ex: Mankind Divided when moving from the NVIDIA GeForce GTX 1080 FE to the GeForce GTX 1080 Ti we saw very nice scaling on the the Intel Core i7-7700K processor as we got 25% gains at 4K, 23% gains at 1440P and 16% gains at 1080P. The AMD Ryzen 7 1700 processor scaled 27% at 4K, 21% at 1440P, but didn't scale at all at 1080P (0.1% doesn't count). It looks like the AMD Ryzen 7 1700 processor at 4GHz on all cores is actually bottlenecking the platform and therefore we get no performance scaling whatsoever by moving up to a GeForce GTX 1080 Ti FE graphics card.

Thief and GTAV

Thief

Thief is a series of stealth video games in which the player takes the role of Garrett, a master thief in a fantasy/steampunk world resembling a cross between the Late Middle Ages and the Victorian era, with more advanced technologies interspersed. Thief is the fourth title in the Thief series, developed by Eidos Montreal and published by Square Enix on February 25, 2014.
This is an older game title, but we wanted to see how an older game title would perform on the latest processors and video cards.

We ran Thief with the image quality settings set at normal with VSYNC disabled.
Benchmark Results:In Thief we found that the move from the NVIDIA GeForce GTX 1080 FE to the GeForce GTX 1080 Ti FE didn't yield huge performance gains as this is an older game title with averages already well into the 100+ FPS range at most all resolutions. We did see some nice scaling at every resolution on both processors on this game title. The Intel Core i7-7700K processor as we got 21% gains at 4K, 7% gains at 1440P and 4% gains at 1080P. The AMD Ryzen 7 1700 processor powered platform gained 17% at 4K, 7% at 1440P and 3% at 1080P.

Grand Theft Auto V

Grand Theft Auto V, currently one of the hottest PC games, was finally released for the PC on April 14, 2015. Developed by Rockstar, it is set in 2013 and the city of Los Santos. It utilizes the Rockstar Advanced Game Engine (RAGE) which Rockstar has been using since 2006, with multiple updates for technology improvements.
In Grand Theft Auto V we set the game to run with no MSAA with 16x AF and high image quality settings as we didn't want the GPU to bottleneck the system too bad, but wanted a setup that your average gamer would actually play on. We used the games built-in benchmark utility to have at least one game we used that could be compared to your setup at home. We averaged all the five of the default benchmark runs and omitted both the minimum and maximum values as those results are garbage due to major inconsistencies.
Benchmark Results:In Grand Theft Auto V we got some very interesting results when we moved from the NVIDIA GeForce GTX 1080 FE to the GeForce GTX 1080 Ti FE. On the Intel Core i7-7700K processor we got 23% gains at 4K, 9% gains at 1440P and 2% gains at 1080P and on the AMD Ryzen 7 1700 processor we got 24% at 4K, 1% at 1440P and basically no improvement at 1080P. This is yet another game title that shows the new GeForce GTX 1080 Ti and even the GeForce GTX 1080 can be bottlenecked to some degree by the processor. In fact, it looks like we are actually CPU-bound or CPU-limited at both 1080P and now even 1440P with the Ryzen 7 series processor. The Intel Core i7-7700K doesn't appear to have any major CPU limitations at 1440P or at least very minor.

Fallout 4 & Ghost Recon Wildlands

Fallout 4Fallout 4 is an open world action role-playing video game developed by Bethesda Game Studios and published by Bethesda Softworks. Fallout 4 is set in a post-apocalyptic Boston in the year 2287, 210 years after a devastating nuclear war, in which the player character emerges from an underground bunker known as a Vault. Gameplay is similar to Fallout 3. The title is the fifth major installment in the Fallout series and was released worldwide on November 10th, 2015.
Fallout 4 was benchmarked with ultra image quality settings with TAA and 16x AF. These settings are tough for entry level discrete graphics cards, but are more than playable on high-end gaming graphics cards. V-Sync can't be disabled in the games options, so we edited the necessary INI files and disabled vsync in the driver software as well. We used FRAPS to benchmark Fallout 4 after you emerge from the vault and are in The Commonwealth.
Benchmark Results:In Fallout 4 we got similar results yet again when we moved from the NVIDIA GeForce GTX 1080 FE to the GeForce GTX 1080 Ti FE. On the Intel Core i7-7700K processor we got 27% gains at 4K,22% gains at 1440P and 14% gains at 1080P and on the AMD Ryzen 7 1700 processor we got 27% at 4K, 16% at 1440P and a small 1.5% gain at 1080P. Ghost Recon WildlandsTom Clancy's Ghost Recon Wildlands is an open world tactical shooter video game developed by Ubisoft Paris. It is the tenth installment in the Tom Clancy's Ghost Recon franchise and is the first Ghost Recon game to feature an open world environment. The game moves away from the futuristic setting introduced in Tom Clancy's Ghost Recon Advanced Warfighter and instead feature a setting similar to the original Tom Clancy's Ghost Recon. Ubisoft described it as one of the biggest open world games that they have ever published, with the game world including a wide variety of environments such as mountains, forests, deserts and salt flats. A modified version of the AnvilNext game engine was used. The game was released on March 7, 2017 for Microsoft Windows, PlayStation 4 and Xbox One.
Tom Clancy's Ghost Recon Wildlands was benchmarked with high image quality settings with Temporal AA and 4x AF. V-Sync and the framerate limit were both disabled and we used the game titles built-in game benchmark.
Benchmark Results:In Tom Clancy's Ghost Recon Wildlands we found nice scaling as we moved from the NVIDIA GeForce GTX 1080 FE to the GeForce GTX 1080 Ti FE on both Intel and AMD processors. On the Intel Core i7-7700K processor we got 22% gains at 4K, 18% gains at 1440P and 14% gains at 1080P and on the AMD Ryzen 7 1700 processor we got 23% at 4K, 17% at 1440P and a 15% gain at 1080P. AMD Ryzen actually scaled 1% better, but was still behind Intel Kaby Lake by 10% at 1080P, 8% at 1440P and 3% at 4K.

Final Thoughts & Conclusions

The new NVIDIA GeForce GTX 1080 Ti Founders Edition graphics card is without a doubt a beast, but you can certainly see that the processor you pick for your desktop gaming PC will play a big role in how the new graphics card performs on 1080P and 1440P display setups. A stock Intel Core i7-7700K processor was able to offer superior gaming performance over the overclocked AMD Ryzen 7 1700 processor. In fact, when it came to 1080P gaming performance the NVIDIA GeForce GTX 1080 Ti was found to be an average of 29.6% faster on the Intel platform on the five game titles we took a look at. The 1440P scores also showed that the average frame rate was 16.6% higher on the Intel platform, so when it comes to 1080P or 1440P gaming performance the Intel Core i7-7700K and NVIDIA GeForce GTX 1080 Ti pair together nicely.
That said, the vast majority of people buying the NVIDIA GeForce GTX 1080 Ti ($699) will likely be gaming at 1440P or higher due to the price point on this new card. AMD also has some work to do with regards to optimizations for Ryzen and promises that some improvements will be coming soon. The NVIDIA GeForce GTX 1080 Ti appears to still be GPU bottlenecked at 4K gaming, but this card is so fast that we are starting to see signs that the CPU is now actually bottlenecking performance at 1440P and lower resolutions. Seeing virtually no average frame rate increase in GTA V on the Ryzen 7 1700 with the GeForce GTX 1080 Ti at 1440P was a bit of a shock, but the numbers don't lie. The NVIDIA GeForce GTX 1080 has had its priced slashed with the release of the new Ti version, so you can pickup a card like the EVGA GeForce GTX 1080 Gaming for just $499 now.
The NVIDIA GeForce GTX 1080 Ti so far feels like it is a great 4K gaming graphics card and we think that by doing this article it has helped us setup our new video card test bench test suite and the image quality settings we'll be using there. Hopefully you enjoyed our quick look at Ryzen versus Kaby Lake with performance scaling by going from the GeForce GTX 1080 to the GeForce GTX 1080 Ti!
Leave us some feedback below and we'll have our full review on the GeForce GTX 1080 Ti in the weeks ahead!
Update 3/14/2017:
A few people have been asking about CPU utilization and how AMD basically is using less and that will allow for them to do more things while gaming and possibly unlock more game performance once optimizations ever arrive. That could be true, but the Intel Core i7 7700K isn't at full load in most game titles. Take a look at these results from Ghost Recon: Wildlands, which is the most recent game title in our test suite and it came out this month.
[caption id="attachment_192676" align="aligncenter" width="645"] Wildlands CPU Usage on Ryzen 1700[/caption]
The AMD Ryzen 7 1700 overclocked to 4GHz averaged 25.3% CPU usage on the 16 available threads and peaked at 35.9%.
[caption id="attachment_192677" align="aligncenter" width="645"] Wildlands CPU Usage on Core i7-7700K[/caption]
The Intel Core i7-7700K averaged 35.7% CPU usage with just 8 available threads and peaked at 42.1% usage, which shows that over half the processor isn't being used.
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